Tag: physics

Questions Related to physics

If a body is moving with a constant speed along a straight line; then in order to change its direction of motion, an external force has to be applied in a direction normal to the direction of motion.

physics along with motion what forces can do? force and it's unit force and its effects

  1. True

  2. False

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Correct Option: A
Explanation:

Newton's First law of motion - "Every body continues to be in its state of rest or of uniform motion in a straight line unless compelled by some external force to act otherwise". 

According to Newton's First law of motion, statement is true, an external force has to be applied in a direction normal to the direction of motion to change its direction of motion

Which of the statements about force are true?

physics along with motion what forces can do? force and it's unit force and its effects

  1. It can be seed

  2. It causes an object to move

  3. It is pull or a push

  4. It can change the motion of an object

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Correct Option: B,C,D
Explanation:

Force cannot be seen as it is a push or pull. But it causes an object to or can also change the motion of an object.

Three forces are acting on a body in which of following option (s) can the body be in equilibrium?

physics along with motion what forces can do? force and it's unit force and its effects

  1. $2N, 4N, 5N$

  2. $1N, 2N, 4N$

  3. $3N, 3N, 7N$

  4. $5N, 2N, 1N$

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Correct Option: A
Explanation:

Three force are in equilibrium if 

1) All forces are in a plane 
2) Sum of two small forces is less than bigger force.
This condition is satisfy by option A
Answerer A

A ball of mass 250 g  moving  with a speed of  hits a wall normally . it rebounds with the same speed . If the two were in contact for , the average force exerted by the wall on the ball is 

physics along with motion what forces can do? force and it's unit force and its effects

  1. $4 \times {10^{ - 3}}N$

  2. $2 \times {10^{ - 3}}N$

  3. ${10^{ - 3}}N$

  4. ${10^{ - 2}}N$

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Correct Option: B

 A force of $15 N$ increases the length ofa by $1 \mathrm { mm }$. The additional force require increase the length by $2.5 \mathrm { mm }$ in N is 

physics along with motion what forces can do? force and it's unit force and its effects

  1. $2.25$

  2. $22.5$

  3. $37.5$

  4. $3.75$

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Correct Option: B
Explanation:

We know,

$Y=\dfrac{FL}{A\Delta L}$

For a wire, A,L,Y are constant.

$\dfrac{F}{\Delta L}=$constant

Let extra Force needed be $ F$,

$\dfrac{15}{1}=\dfrac{F+15}{2.5}$

$F+15=2.5\times 15$

$F=1.5\times 15=22.5$

Option $\textbf B$ is the correct answer

The force between two identical bar magnets whose centers are r meter apart is $2.8$N when their axis are in the same line. If the separation is increased to $2r$ meters, the force between them is reduced to

physics along with motion what forces can do? force and it's unit force and its effects

  1. $2.4N$

  2. $1.2$N

  3. $0.7$N

  4. $0.175$N

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Correct Option: C

A lift coming down is just about to reach the ground floor. Taking the ground floor as origin and positive direction upwards for all quantities, which of the following is correct ($x$=displacement, $v$= velocity, $a$=acceleration):

physics along with motion what forces can do? force and it's unit force and its effects

  1. $x < o, v<0, a>0$

  2. $x > 0, v < 0, a < 0$

  3. $x > 0, v < 0, a> 0$

  4. $x > 0, v >0,a >0$

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Correct Option: A

A particle moves in a potential region given by $U = 8{x^2} - 4x + 400\,J.$ Its state of equilibrium will be$-$ 

physics along with motion what forces can do? force and it's unit force and its effects

  1. 8 m

  2. 10 m

  3. 12 m

  4. 0.25 m

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Correct Option: D
Explanation:

$U = 8x^2 - 4x + 400$
Differentiate with $dx$ we will get $F$
$F = 16x - 4$
At equilibrium $F = 0$
$0 = 16x - 4$
$x = 1/4 = 0.25 m$
It’s state of equilibrium will be at $x = 0.25 m$

Hence,
option $(D)$ is correct answer.

Which of Newton's three laws does the following example illustrate? If you have a hockey pick sliding along a table, it will eventually come to a stop.

physics along with motion what forces can do? force and it's unit force and its effects

  1. Newton's First Law

  2. Newton's Second Law

  3. Newton's Third Law

  4. All of the above

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Correct Option: A,B,C,D

A force produces transnational motion:

physics along with motion what forces can do? force and it's unit force and its effects

  1. when the body is free to move

  2. when the body is hindered to move

  3. when the body is rigidly fixed

  4. when none of the above are true

Show answer
Correct Option: A
Explanation:

For the application of translational motion the body must be free to move and after applying force, all the particles in that body move with same velocity.